Considering the insane amount of creativity showed 'til now I don't think Caribdis is thinking about that.
I mean given the amount of details, branched plots, and the hot and adorable girls already shown in Eternum ( that is still in it's initial phase, and this thing alone is mind blowing) and that show promises to be way more bigger and longer than is predecessor, I don't see him/her turning back to this story in the near future.
Maybe if he/she will feel the need to say something more it's possible to have a sequel, never say never as the say goes, but I don't have the feeling he/she is one of those authors that will came back to milk more from a game ( even though it was a great game), instead looks like he/she have a lot up his sleeve to create.